Operating mechanism for spray guns



Nov. 27, 1956 G. GODA OPERATING MECHANISM FOR SPRAY cums Filed March 5, 1954 IN V EN TOR. GEORGE 600.

A T7'ORNE Y United States Patent OPERATING MECHANISM FOR SPRAY GUNS George Goda, Brooklyn, N. Y., assignor to Champion Implement Corp., New York, N. Y., a corporation of New York Application March 5, 1954, Serial No. 414,262

3 Claims. (Cl. 299-97) -'Ihe present invention is directed to spray guns, more particularly to an electrically operated device which is adapted to spray various liquids including lacquers and the like.

Spray guns operated electrically have been known for some time and have been used in industry. Among such types of spray guns is one which utilizes the vibrations of an-armature of an electromagnet. The armature vibrates at a high rate and the amount of power required is relatively low. The spray gun also has a cylinder with a piston therein which reciprocates due to the action of the vibrating armature. In some of the prior devices on the market there was rapid wear due to the high speed of vibration of the piston and the mounting of the several elements associated therewith. As a result, the spray gun after but a short period of use ceases to function properly and may fail altogether.

The present invention is intended and adapted to overcome the difiiculties and disadvantages inherent in prior devices of the type described, it being among the objects of the present invention to provide a spray gun having a novel construction of cylinder piston and associated elements which is capable of functioning continuously for long period-s of time without deterioration.

It is also among the objects of the present invention to provide a cylinder and piston arrangement which is readily assembled in production and which may be easily dismounted for repair or cleaning purposes.

It is further among the objects of the present invention to provide a device of the character described in which leakage is practically eliminated and binding of or interierence with the purpose of the piston is practically eliminated. In practicing the present invention there is provided a spray gun of the Well known type having a body portion, a cylinder mounted in the body with a piston reciprocating therein. At one end the piston is opera-ted by the vibration of the armature and at the other end it operates in the cylinder pumping a liquid from a container and forcing it out through a spray nozzle at the opposite end of the cylinder. In accordance with the present invention the cylinder is relatively short and the piston is relatively long. The cylinder has at the rear end thereof an opening of a diameter larger than that of the main cylinder. A cylindrical sleeve fits into the enlarged portion of the cylinder and the piston passes through the sleeve being supported therein at the free end of said sleeve. The extreme end of the piston is provided with a spring arrangement, bearing against the sleeve for the purpose of maintaining contact of the piston with the armature during the entire cycle of operation.

*In the accompanying drawing constituting a part hereof and in which like reference characters indicate like parts,

Fig. 1 is a vertical cross-sectional view of a spray gun made in accordance with the present invention, some parts being shown in elevation for clearness;

Fig. 2 is a vertical cross-sectional view of the spray gun of Fig. 1, some parts being omitted and other parts being shown in elevation; and

Fig. 3 is a fragmentary transverse cross-sectional view taken along line 3--3 of Fig. 2.

With reference to Fig. 1, the spray gun has a casing made in two identical halves, 1 land 1' which are bolted together in the usual manner to form the casing or body of the spray gun. It has a handle 2 for grasping by the operator. A support 3 holds sleeve 4 connected to a cylinder and spray nozzle '5. An electromagnet 6 within handle one has a vibrating .armature 7 anda switch 8 and adapted to be pressed by the finger of the operator to close the circuit of the electromagnet. An adjusting screw 9 having a spring 10 is adapted to contact the end of the armature to adjust the arc of vibration thereof.

*Integral with the body 1 and depending therefrom is a cylindrical member :11, having a skirt 12 threaded internally. A glass jar or the like 13 is held within skirt '12 and contains the liquid to be sprayed. A washer 14 provides a liquid tight seal. Tube 15 depending from the body of the spray gun has a flexible tube .1-6 at the lower end thereof. The end of the flexible tube is immersed in the liquid in jar 13.

The upper end of tube 15 is threaded into a corresponding part of body 1 adjacent to the cylinder. A nut 19 on the threaded portion of tube '15 holds the latter in fixed position.

The sleeve 4 has a reduced outer end 20 forming a shoulder 21. A cylinder block 22 has a bore 23 in which a cylindrical piston or plunger 24 is adapted to slide. The left hand side of cylinder block 22 has an enlarged diameter into which the reduced portion 20 is frictionally engaged with shoulder 21 abutting against the end of cylinder block 22. A ball valve 25 within cylinder block 22 is adapted to seat at the right hand end of bore 23 and a spring 26 is interposed between ball 25 and nozzle 5. An opening 27 connects tube 15 to bore 23 to allow a passage of liquid from jar 13 into the spray gun.

A sleeve 4 has over most of its length an internal diameter 28 which is greater than the external diameter of piston 24, thereby friction between the sleeve and piston is avoided and accidental binding of the two parts is eliminated. At the right hand end of sleeve '4 and at the point where the bore 23 meets the enlarged diameter of cylinder block 22, there is provided an O-ring washer 29 which provides a seal to prevent accidental escape of liquid from bore 23. in the left hand end of sleeve 4 is an oilless bearing 31 which may be of any suitable type on the market and which provides adequate lubrication so as to avoid wear of piston 24. At the extreme left hand end of said piston there is threaded a head nut 32 which is contacted by the end :of armature 7 to cause vibration of the piston. A coil spring 33 surrounds the end of piston 24 with one end bearing against nut 32 and the other end bearing against washer 30, which in turn is in contact with bearing 31.

In the operation of the spray gun liquid is placed in jar 13, switch 3 is pressed, closing the circuit of electromagnet 6 and resulting in vibration of armature 7. This causes piston 24 to move forward under the impact and to be retracted by the action of spring 33. Thus rapid vibration of piston 24 is accomplished. Such vibration alternately covers and uncovers opening 27 so that liquid is drawn up through tube 15 by retraction of plunger 24 and is forced out through the nozzle by the reverse movement of piston 24. The piston acts as a valve to close oii tube 15 in its movements.

In order to prevent leakage between the upper end of tube 15 and bore 23, there is provided an enlargement 34 below opening 27. A flat washer 35 is inserted in said enlargement 34 between the end face of tube '15 and said enlargement. The action of nut 19 provides a close tit and avoids leakage.

Although the invention has been described setting forth one specific embodiment thereof, the invention is not to be limited thereto as various changes in details of construction may be made within the spirit of the invention. 7 For instance, the mounting of cylinder block 22 and sleeve 4 maybe different from that shown and described. Tube 15 may have connected to the lower end' thereof a flexible tube so that liquid from the corners, of

' jar 13 may be fed to thespnay gun. Washer 29 may the of suitable material, such :as a natural or'syntheti-c rubber composition. Thesize and relative proportions of the several parts may be altered and equivalent elements may be substituted for the specific elements. described herein.

' Various materials of construction suitable for the purpose nozzle, the inner diameter of said sleeve being greater than the di-ameter of said piston, a lubricating bearing in .the opposite end of said sleeve, said pistonextending through said sleeve and bearing, said cylinder having'an enlarged diameter into which said sleeve -fits and a ring washer between the end of said sleeve and the shoulder formed at the junction of the two diameters of said cylinder. i v p g 2. in a spray gun having abody, a cylinder mounted in said body, a piston operating therein, a spray nozzle at one end thereof and means for reciprocating said piston, the improvement which comprises a sleeve .one end of which is secured to the end of said cylinder opposite said nozzle, the inner diameter of said sleeve being greater than the diameter of said piston, a lubricating bearing in V the opposite end of .saidsleeve, said piston extending through said sleeve and bearing, an opening in the side of said cylinder, a tube extending into said opening, said tube being threadedinto said body, and t3. washer at the end of said tube adjacent said opening.

"3. In a spray gun having a body, a cylinder mounted in said body, a piston operating therein, a spray nozzle at one end thereof and means for reciprocating said piston,

the improvement which comprises a sleeve one end of which is secured :to the end of said cylinder opposite said nozzle, the inner diameter of said sleeve being greater than the diameter of said piston, alubricating bearing in the opposite end of said sleeve, said piston extending through said sleeve. and bearing, said cylinder having an enlarged diameter into which said sleeve tits and a ring washer between the end of said sleeve and the shoulder formed at the junction of the two diameters of said cylinder, a shoulder on the outer face or" said sleeve, said shoulder being seated against the end of said cylinder block.

References Cited in the file of this patent UNITED STATES PATENTS Simmons Jan. '17, 1950 Duncan Oct. 7, 1953 

